The present invention relates generally to hand tools used in construction, and, more particularly, to masonry tools for determining that masonry construction is plumb, square and level.
A large number of carpentry tools have been invented to measure whether framing elements such as studs, rafters or joists are level, square and plumb. Masonry construction requires similar measurements, but in contrast to framing, masonry construction utilizes smaller individual elements such as bricks, stones, and blocks; and carpentry tools either are improperly sized or do not contain the correct combination of tools to optimally be used for masonry. With masonry there is a greater reliance on craftsmanship to achieve satisfactory results. For instance, when building a chimney out of brick, the brick layer must keep the construction straight, level and square. A small error at the beginning, can result in a significant error in the completed chimney. A 30 foot chimney deflected just 3xc2x0 from plumb will be deflected 1.5 feet at the top of the chimney.
What is needed is a masonry tool that can confirm that construction is square, plumb, and that an individual element such as a brick or a block is level, and a tool that can confirm that a composite of individual elements is plumb and level.

Applicant is aware of the following U.S. Patents concerning framing squares:
The invention is a masonry tool useful for confirming that masonry work is square, level and plumb. The invention is an integrable framing square with an articulatable retractable straightedge, where the integrable framing square can be retrofitted to a level. As an article of manufacture, the invention is a framing square with an articulatable retractable straightedge integral to a level, where the articulatable retractable straightedge is rotatable to a right angle. Additional angles, such as 45xc2x0 and 135xc2x0, can also be designed into the invention. The articulatable element of the invention is substantially a retractable straightedge that is locked, except when rotating to a new position. When retracted, the straightedge is substantially flush or slightly recessed beneath an edge of the level. The retractable straightedge is unlocked by depressing a finger activated lock which disengages a spring loaded lock. Without the need for further finger pressure, the retractable straightedge can be folded out until it snaps into a right angle position, where it is locked. The process can be reversed by simply depressing the finger activated lock and rotating the retractable straightedge back against the level, where it re-locks. Alternatively, the retractable straightedge can be folded out further to 135xc2x0 (90xc2x0+45xc2x0). The process can be reversed by simply depressing the finger activated lock, and rotating the retractable straightedge back against the level, where it re-locks.
Preferably, the retractable straightedge is a flat bar marked with rulings and indicia. In the right angle position the flat bar creates a visually enhancing perspective of any deviation from either a pure right angle, or a deviation from plumb. The retractable straightedge has a length that is sufficient to determine that a brick or block is square and level. For a typically concrete or clay brick, the straightedge should have a minimum length of approximately 0.5 feet and maximum length of 4 feet. A preferred length is 1 foot to 1.5 feet, or approximately the length of at least one block or brick. Straightedges longer than 4 feet are subject to deflecting under their own weight unless especially designed, and they are rather unhandy.
The retractable straightedge pivots at the end of a housing which is mounted to an end of the level. The housing contains a rotatable lockable mechanism which enables rotation and locking of the articulatable retractable straightedge. The rotatable lockable mechanism is joined to the articulatable retractable straightedge, so that when the retractable straightedge is articulated, the mechanism rotates accordingly. The rotatable lockable mechanism is substantially a notched disk, where a notch position corresponds to an angle of rotation. The notched disk is mounted on an axial shaft which is affixed to the housing. There is optionally at least one low friction washer mounted between a side of the housing and the notched disk. The housing also contains a finger activated lock, wherein the finger activated lock is connected to a spring loaded slideable pin which can slide into a notch on the disk. The spring loaded slideable pin is secured to a side of the housing a mounting. In its at rest position, the pin impinges one of the notches, and the disk cannot rotate, and hence the articulatable retractable straightedge is secured. Depressing the finger activated lock causes the spring to compress and the slideable pin to move out of the notch, therein freeing the disk to rotate. The framing square optionally includes a faux cover that snaps onto a corner of the framing square. The faux cover helps prevent dirt and mortar and other detritus form getting into the housing and interfering with the operation of the working/moving elements of the framing square, and also serves to extend the functional length of the level""s straightedge and squareness.
In a typical usage, the retractable straightedge is folded out from the level to a right angle position, and at that point the pin encounters the right angle notch and slides into the notch, therein stopping any further rotation. The retractable straightedge can be rotated another 45xc2x0 by again depressing the finger activated lock, which shifts the spring loaded slideable pin out of the right angle notch, and rotating the retractable straightedge until the pin encounters another notch, wherein it will slide into the notch locking the retractable straightedge in the 135xc2x0 angle (90xc2x0+45xc2x0). The action of the slideable pin moving into a notch creates a sound that is a single click.
By addition of other additional notches, further angles could be selected. A potential downside to the addition of notches is that it will become less clear to the user exactly how many clicks the retractable straightedge element must rotate in order to achieve a 90xc2x0 and a 45xc2x0 angle. By selecting only three positions, or three notches, the limited number of selectable angles lessens the probability of error by the user.
The framing square has a mounting bar integral with the housing, such that the framing square can be mounted to a level. The housing affixes collinearly, abutting to the end of the level and the mounting bar attaches to a longitudinal edge side of the level. The level can be produced with the framing square, or an existing level can be fitted with the framing square. In the latter case a preferred method of affixing the housing is to use fastening elements, such as spikes or studs, which project from a front portion of the housing of the housing and intersect with the butt end of the level. Spikes seated in the front portion of the housing can be press fitted into a wooden level, and aluminum level typically have a rubber pad fastened to the end of the level with one or more screws and removing the rubber pad exposes holes for receiving studs. The mounting bar is attached using conventional fastening components such as screws. The mounting bar has countersunk holes so that the fastening components are flush or slightly recessed. The length of the mounting bar is preferably sufficient to extend the entire length of the longitudinal edge side of the level.
The invention provides for an alternative fabrication for a contractor""s level with a squaring frame with a retractable straightedge, where the squaring frame is integral to an end of the level. The squaring frame enables the measurement of both 90xc2x0 and 45xc2x0 angles. The framing square is fitted to a level having a partially cutaway portion of a distal end of the level. With the alternative fabrication, the partially cutaway portion of the level forms one of the sides of the housing of the framing square. The opposing side of the housing is fastened to the partially cutaway portion of the level.
The principal object of the present invention is to provide an article of manufacture that is an integrable framing square with a retractable straightedge that can be fitted to a level.
A further object of this invention is to provide a framing square having a retractable square that is integral to a level.
Another object of the invention is to provide an apparatus, comprising a level and framing square, that is particularly well suited for use with masonry construction.
Another object of the invention is to provide an apparatus that is robust and easy to use.
Another object of the invention is to provide a level with a framing square, wherein the straightedge of the framing square is collapsible, such that the framing square can be reversibly taken out of service.
Another object of the invention is to provide a framing square which can be fitted to a level, therein becoming integral with the level.